Oscillopsia and reduced visual acuity due to retinal image slip caused by acquired nystagmus, and in particular by downbeating nystagmus, can be temporarily reduced or eliminated by a single dose of clonazepam and a sustained beneficial effect can be obtained with daily use of clonazepam. Ocular motor abnormalities in Kallman's syndrome suggest that dysfunction of the cerebellar vermis may also be part of this syndrome. Eye movement abnormalities in multisystem atrophy (Shy-Drager Syndrome) and olivoponto-cerebellar atrophy were studied to provide diagnostic and prognostic information. Studies of eye movements in patients with familial Alzheimer's disease and their first order (at risk) relatives attempt to provide additional diagnostic, prognostic and therapeutic monitoring information. Saccadic velocities have been shown to be a sensitive indicator of benzodiazepine drug effects in man. Caffeine acts as a benzodiazepine antagonist for the degradation of saccadic velocities but not for cognitive function, suggesting different benzodiazepine receptor functions for these two parameters. Carbamazepine induced downbeating nystagmus in two patients without craniocervical abnormalities and this resolved when carbamazepine levels were reduced.